In a chemical reaction, how is the mass of reactants related to the mass of products?

In a chemical reaction, the law of conservation of mass states that mass cannot be created or destroyed in a closed system. This principle ensures that the total mass of the reactants will always equal the total mass of the products formed. When a reaction occurs, the atoms that make up the reactants are rearranged to form the products, but the total number and type of atoms remain consistent throughout the reaction.

This relationship allows us to calculate the amounts of substances involved in the reaction accurately. Therefore, it is essential to understand that even though the substances may change form, their combined weights do not change. This principle is foundational in stoichiometry, where balanced chemical equations represent the quantities of reactants and products, affirming that their masses are equal throughout the process.